Effect of aggregate on aggregate/spinel matrix bonding interface and mechanical performance of lightweight spinel-bonded refractory

In this study, lightweight refractory was fabricated via carbothermal reduction of MgO. The process proceeded by oxygen diffusion rate controlled oxidation of Mg vapor and subsequent reaction between deposited MgO and Al2O3. The aggregate had an obvious effect on the characteristics of the aggregate/spinel matrix bonding interface and mechanical performance of lightweight spinel-bonded refractory. Microcracks appeared at the interface between periclase aggregate and in-situ formed spinel matrix due to the high residual thermal stress of 2047 MPa. But the in-situ formed spinel matrix connected well with the spinel aggregate. Unlike the periclase and spinel aggregate, the corundum aggregate reacted with MgO deposited on its surface to form spinel, and this resulted in strong interface bonding between the corundum aggregate and spinel matrix, which significantly enhanced the mechanical property of spinel-bonded corundum refractory.